When fermenting grape juice is too sweet, yeasts can’t convert all the sugar into alcohol, leaving behind residual sugar.
The Method: Botrytis
The Wines:
Sauternes, Barsac, Tokaji, Ausbruch, Bonnezeaux, Quarts de Chaume, Coteaux de Layon, Sélection des Grains Nobles, Beerenauslese, Trockenbeerenauslese
How it Works:
Botrytis cinerea is a fungus. In wet conditions, it destroys grapes, but when the grapes are ripe and the temperature and humidity are just right, it becomes the so-called “noble rot” pulling moisture out of the grape, leaving behind a shriveled berry with ultraconcentrated sugars, acids and flavors.
The Method: Drying on the Vine
The Wines:
Jurançon, Cordon-Cut Australian Riesling
How it Works:
Some grapes dry out on the vine, a process known as passerillage. Sometimes, growers help the process along by twisting grape clusters to cut off sap flow, or by slashing vine branches.
The Method: Late Harvest
The Wines:
Spätlese, Auslese, Vendange Tardive
How it Works:
The juice of late-harvested, ripe grapes are packed with sugar, and can be affected by passerillage or botrytis.
The Method: Drying on Racks
The Wines:
Amarone, VIN Santo, Recioto, Pedro Ximénez, Passito
How it Works:
Ripe grapes are harvested and then partially dried in the sun or air, causing water loss. In Italy, grapes are dried in well-ventilated lodges and lofts, a process known as apassimento. In Spain, Pedro Ximénez grapes are dried in the sun on esparto-grass mats to make PX wines that taste just like dark raisins.
The Method: Freezing
The Wines:
Eiswein, Icewine
How it Works:
Frozen-solid grapes are harvested and pressed immediately, making it easier to separate the frozen water from the rich, concentrated juice. Of course, modern freezers units can mimic the process.
Halting Fermentation
Actively preventing yeasts from converting all of the sugar during fermentation.
The Method: Fortification
The Wines:
Port, Rivesaltes, Maury, Muscat de Beaumes de Venise, Rasteau VIN Doux Naturel, Banyuls, Rutherglen Muscat and Topaque, Madeira
How it Works:
Adding alcohol kills the yeast and stops fermentation, allowing sugar to remain. Most wines are fortified mid-fermentation, but adding alcohol in the beginning is called mutage, a process used in making Pineau de Charentes, a grape-based aperitif.
The Method: Cooling and Filtering
The Wines:
Kabinett, Moscato d’Asti, California Blush styles, Prosecco
HOW IT WORKS:
Another way to stop yeast in its tracks is by cooling it during fermentation. Once cold, the wine is sterile-filtered to remove the yeasts, leaving sugar behind.
Adding Sugar
The Method: Adjusting sweetness at bottling
The Wines:
Sparkling
How it Works:
When sparkling wines like Champagne, Crémant or Franciacorta are taken off the lees after the second fermentation (the stage that adds bubbles), sugar is added. Called dosage, it creates the dry-sweet character of extra brut, brut, extra-dry and demi-sec. When a bottle says “brut nature” or “zero dosage,” the wine has not been sweetened. Because of the high acidity in most sparkling even with added sugar, many will drink dry. Aged sweet wines can also be used. This happens in the best sparkling Shiraz styles, and the best Riesling-based Sekts.
You’re Shopping List
- Eden Ice Cider Heirloom Blend (Vermont)This cider has a Riesling-esque character, with racy pineapple and lush mango tones. Serve with a cheese plate.
- Joseph Phelps 2013 Eisrébe (Napa Valley)
Floral, with subtle hints of apricot and honey, this is made from Scheurebe, a rarity in California. Best with panna cotta.
- Red Tail Ridge 2012 Sticky Riesling (Finger Lakes)
Unctuous, with spine-tingling, lemony acidity, it’s made from partially botrytized fruit. Pair with fruit pies.
- Gordon Estate 2012 Late Harvest Gewürztraminer (Columbia Valley)
Rich aromatics and flavors of brown sugar, papaya and dried pineapple. Drink straight, while snuggling.
- Calera 2013 Viognier Doux (Central Coast)
Sexy, with racy, lemonade acidity, dried apricot and honeydew, ideal for a fireside tête à tête.
- Inniskillin 2012 Niagara Estate Riesling Icewine (Niagara Peninsula)
Sweet but balanced, with intense flavors of pineapple, mango and honey. Best with crème brûlée.
—Anne Krebiehl
***Grabbed from: http://www.winemag.com/February-2015/Sweet-Wine-Primer/